1. Field of the Invention
The invention relates to the compressed information storage of characters consisting of black and white areas which are to be displayed or printed, and more particularly to apparatus for decompressing stored compressed character information.
2. Description of the Prior Art
Several prior arrangements are known for the output of characters made up of black and white areas. In computer controlled alpha-numeric character generators, the characters are initially stored in an encoded form to be subsequently converted by means of decoders into graphical information for character output. The more sophisticated arrangements are able to handle characters of different fonts and sizes. To this end storages are required which contain the information necessary for displaying or printing the various characters. For each character of a particular size and font, font storages contain specific information for controlling the output of the character. However, for large amounts of data, i.e., for applications involving a plurality of different character sizes and fonts, the size of the font storages becomes excessive. Previously, for cost reasons, attempts were made to keep the size of such storages as small as possible. To achieve this, the amount of data required for character output was reduced with the aid of compressed information storage. A known method of this kind is known as "run length coding," whereby compression is effected by storing the length data of the black and white areas of the characters divided into columns. See U.S. Pat. No. 3,582,905, Character Generation by Improved Scan, Storage, and Decoding Apparatus, H. P. Kraatz et al., filed Jan. 13, 1969, issued June 1, 1971, and assigned to IBM.
However, this method did not solve the problem of character staggering wherein characters are above or below the print line, and did not permit the output of characters over several lines.